U.S. patent number 5,126,794 [Application Number 07/669,713] was granted by the patent office on 1992-06-30 for corona wire tape assembly.
This patent grant is currently assigned to Eastman Kodak Company. Invention is credited to Conrad Altmann.
United States Patent |
5,126,794 |
Altmann |
June 30, 1992 |
Corona wire tape assembly
Abstract
A corona wire tape assembly for a corona charger apparatus, such
wire tape assembly providing for a more durable corona wire which
is kept substantially clean and which can readily be replaced. The
corona wire tape assembly comprises at least one conductive wire
adapted to generate ions when having a high voltage from an
electrical potential source applied thereto. A flexible dielectric
film, separable into lengths substantially corresponding to desired
corona wire lengths, encases the conductive wire. The flexible
dielectric film defines a first series of openings communicating
with the conductive wire to expose the wire to facilitate ion
generation and a second series of openings communicating with the
conductive wire to facilitate electrical connection of the wire to
an electrical potential source.
Inventors: |
Altmann; Conrad (Rochester,
NY) |
Assignee: |
Eastman Kodak Company
(Rochester, NY)
|
Family
ID: |
24687417 |
Appl.
No.: |
07/669,713 |
Filed: |
March 15, 1991 |
Current U.S.
Class: |
399/170; 250/324;
361/225 |
Current CPC
Class: |
G03G
15/0291 (20130101) |
Current International
Class: |
G03G
15/02 (20060101); G03G 015/02 () |
Field of
Search: |
;355/219,221,220,223,225,226 ;361/225,230 ;250/324,325,326
;174/117F |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Grimley; A. T.
Assistant Examiner: Lee; Shuk Y.
Attorney, Agent or Firm: Kessler; Lawrence P.
Claims
I claim:
1. For use with a corona charger apparatus, a corona wire tape
assembly for forming the corona wire for said charger apparatus,
said tape assembly comprising:
at least one conductive wire adapted to generate ions when having a
high voltage from an electrical potential source applied thereto;
and
a flexible dielectric film separable into lengths substantially
corresponding to desired corona wire lengths, said flexible
dielectric film encasing said at least one conductive wire and
defining a first series of openings communicating with said at
least one wire to expose said wire to facilitate ion generation,
and further defining a second series of openings communicating with
said at least one wire to facilitate electrical connection of said
at least one wire to an electrical potential source.
2. The invention of claim 1 wherein said flexible dielectric film
is of cast construction having said at least one conductive wire
imbedded therein.
3. The invention of claim 1 wherein said flexible dielectric film
is constructed as a pair of dielectric films having said at least
one conductive wire sandwiched therebetween.
4. The invention of claim 1 wherein said flexible dielectric film
includes means for affixing said corona wire tape assembly to a
substrate.
5. The invention of claim 1 wherein said affixing means includes an
adhesive layer coating.
6. The invention of claim 1 wherein said flexible dielectric film
includes a flexible metallic layer to provide a ground plane.
7. The invention of claim 1 wherein said flexible dielectric film
is in the form of an elongated flat tape.
8. The invention of claim 1 wherein said first series of openings
are perforations respectively formed in one surface of said
tape.
9. The invention of claim 1 wherein said second series of openings
are perforations respectively formed in one surface of said
tape.
10. The invention of claim 1 wherein said first series of openings
are perforations respectively formed in one surface of said tape,
and said second series of openings are perforations respectively
formed in the opposite surface of said flat tape.
11. The invention of claim 10 wherein said perforations of said
first series of openings are relatively closely spaced, and said
perforations of said second series of openings are relatively
spaced at substantially greater intervals than said first mentioned
perforations.
12. The invention of claim 1 including a plurality of conductive
wires.
Description
BACKGROUND OF THE INVENTION
This invention relates generally to corona charger apparatus, and
more particularly to corona wire in the form of a tape assembly for
corona charger apparatus.
In many types of printing apparatus, such as for example
electrostatographic reproduction devices, it is common practice to
use corona charger apparatus to provide an electrostatic field for
various purposes such as uniformly charging a dielectric support or
transferring a marking particle developed image from the dielectric
support. Typical corona charger apparatus include a thin wire,
fabricated of tungsten for example, to which a high voltage is
applied to generate ions or charge current to charge a surface
(dielectric support or receiver member) located closely adjacent to
the charger apparatus. If desired, an electrically biased grid may
be interposed between the wire and the surface to control the
charge deposited on the surface. The corona wire is tightly
suspended between two insulating blocks which also provide a
support for a connection to a high voltage source. Tension in the
corona wire must be accurately set in order to prevent undesirable
sagging of the wire if the tension is insufficient or breakage of
the wire if the tension is too high. Since the corona wire is thin,
it is fragile and setting and maintaining proper tension is
difficult.
Further, while corona charger apparatus are noted for their ability
to produce a relatively uniform charge deposit on a surface, the
wire of the charger apparatus deteriorates over time. Such
deterioration results in non-uniformity of the charge deposit with,
for example, a corresponding degradation of the information
reproduced by an electrostatographic reproduction device employing
such corona charger. Accordingly, the corona charger apparatus wire
must be periodically replaced to maintain high quality
reproductions.
SUMMARY OF THE INVENTION
This invention is directed to a corona wire tape assembly for a
corona charger apparatus, such wire tape assembly providing for a
more durable corona wire which is kept substantially clean and
which can readily be replaced. The corona wire tape assembly
comprises at least one conductive wire adapted to generate ions
when having a high voltage from an electrical potential source
applied thereto. A flexible dielectric film, separable into lengths
substantially corresponding to desired corona wire lengths, encases
the conductive wire. The flexible dielectric film defines a first
series of openings communicating with the conductive wire to expose
the wire to facilitate ion generation and a second series of
openings communicating with the conductive wire to facilitate
electrical connection of the wire to an electrical potential
source.
The invention, and its objects and advantages, will become more
apparent in the detailed description of the preferred embodiment
presented below.
BRIEF DESCRIPTION OF THE DRAWINGS
In the detailed description of the preferred embodiment of the
invention presented below, reference is made to the accompanying
drawings, in which:
FIGS. 1a-1c are end elevational views, in cross-section, of
respective embodiments of the corona charger apparatus wire tape
assembly according to this invention;
FIG. 2 is a top view, in perspective, of the corona charger
apparatus wire tape assembly according to this invention in its
unrolled form, showing the small perforations therein; and
FIG. 3 is a bottom view, in perspective, of the corona charger
apparatus wire tape assembly according to this invention in its
unrolled form, showing enlarged perforations therein for connection
to a source of electrical potential;
FIG. 4 is a view, in perspective, of the corona charger apparatus
wire tape assembly according to this invention in its rolled form
for storage; and
FIG. 5 is a cross-sectional view, in perspective, of a corona
charger apparatus employing the wire tape assembly according to
this invention, with portions broken away or removed to facilitate
viewing.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to the accompanying drawings, FIGS. 1a-1c show the
wire tape assembly, designated generally by the numeral 10,
according to this invention. The wire tape assembly 10 comprises at
least one thin conductive wire 12 (plurality of substantially
parallel wire shown in the embodiment of FIG. 1c) encased in an
elongate flexible dielectric film 14. The wire 12 may be made of
any conventional conductive filament material such as stainless
steel, gold, aluminum, copper, tungsten, or platinum for example.
The film 14 may be made of any conventional flexible dielectric
material such as polyethylene terephthalate for example.
Construction of the wire tape assembly 10 may be alternatively
accomplished as follows. In the embodiment shown in FIGS. 1a and
1c, two layers of film 14a, 14b are formed in intimate contact with
the conductive wire(s) 12 sandwiched therebetween; in the
embodiment shown in FIG. 1b, the conductive wire 12 is imbedded in
a single layer of cast film 14. With either method for forming the
wire tape assembly 10, a layer 16 of any suitable adhesive coating
may be applied to one surface of the dielectric film 14. The
adhesive coating layer 16 enables the wire tape assembly to be
mounted to a suitable substrate as will be described below with
reference to FIG. 5. Further, if the corona apparatus which will
employ the wire tape assembly according to this invention requires
a ground plane, a suitable conductive metallic film 18 can be
formed, as the ground plane, in association with a surface of the
dielectric film 14 (see FIG. 1b).
A first surface S.sub.1 of the dielectric film 14 has a series of
relatively small, closely spaced perforations 20 formed therein
(see FIG. 2). The perforations 20, which may be formed as an
integral part of the film or drilled therein at some subsequent
time, are located to communicate with the conductive wire(s) 12.
The wire is thus exposed to the atmosphere so that upon application
of a high voltage potential to the wire generation of air ions is
facilitated. The surface S.sub.2 of the dielectric film 14
(opposite to the surface S.sub.1) has a series of relatively large
perforations 22 formed therein (one shown in FIG. 3). The
perforations 22, which may be formed as an integral part of the
film or drilled therein at some subsequent time, are located to
communicate with the conductive wire(s) 12 at a spacing therealong
substantially equal to the desired length of the corona wire for a
selected corona charger apparatus. The wire 12 is exposed by the
perforations 22 so that electrical contact with a high voltage
potential source can readily be effected.
With the wire tape assembly 10 according to this invention
constructed in the above described manner, the wire tape can be
formed into a roll 30 as shown in FIG. 4. In this rolled form, the
wire tape assembly is easily carried or stored and provides maximum
protection prior to use. Further, a desire length of the wire tape
assembly 10 can be easily unrolled and separated from the roll 30
for use in a corona charger to initially provide the corona wire or
replace corona wire tape assembly as required.
The use of the wire tape assembly 10 constructed according to this
invention in a corona charger is shown in FIG. 5. The exemplary
corona charger, designated by the numeral 40, includes a body 42
having a portion 44 adapted to serve as a corona wire supporting
substrate. An appropriately selected length of the wire tape
assembly 10 is fixed to the substrate, such as by adhesive
attachment through the previously described adhesive layer 16. The
substrate portion 44 of the corona charger 40 is particularly
configured such that the wire 12 of the assembly 10, conforming to
the substrate portion, is accurately located relative to the corona
charger body 42 and thus the apparatus (not shown) with which the
corona charger is to be associated. An electrical contact post 46
is supported in the body 42 and extends through the portion 44 to
engage the wire 12 through the communication perforation 22. The
post 46 can then be coupled to a high voltage potential source 48
to enable high voltage to be applied to the wire 12 during desired
operation of the corona charger.
As can readily be appreciated, the use of the wire tape assembly 10
according to this invention in a corona charger 40 provides unique
advantages over conventional corona charger wires. The wire 12 of
the wire tape assembly 10 is substantially protected from
contamination, and is thus less likely to cause charger induced
defects due to contamination. Also, there is no requirement that
the wire 12 be maintained under a particularly tension to remain in
proper relation to the charger body or the apparatus with which the
corona charger is associated. The supporting substrate portion 44
of the corona charger can be designed to locate the wire at a
particularly desired relation to the corona charger and thus the
apparatus with which the corona charger is associated. Since the
wire 12 is protected by the flexible dielectric film 14 and not
kept under tension, the wire itself can be of a smaller diameter
and be formed from weaker materials than heretofore utilized. Such
attributes of the wire have been found to be desirable in that
smaller diameter wires generate stronger electrical fields and
certain weaker material (such as gold for example) are more
corrosion resistant.
The invention has been described in detail with particular
reference to preferred embodiments thereof, but it will be
understood that variations and modifications can be effected within
the spirit and scope of the invention.
* * * * *